1. Field of the Invention
The present invention relates to a shipping container for transporting highly toxic waste materials or radioactive waste materials which emit low and/or medium levels of radiation. In particular, the present invention relates to a light weight and leak-tight shipping container for transporting said materials in a safe and efficient manner.
2. Description of the Prior Art
Shipping containers which are used to transport nuclear waste materials, for example waste materials containing plutonium in excess of 20 curies per package, as specified by the Nuclear Regulatory Commission of the United States Government in 10 C.F.R. .sctn. 71, must be packaged in a separate inner container placed within an outer container. Both the inner and outer containers must be sealed in a leak-tight manner so that no radioactive particles or gases are released during transit. The shipping containers must be highly resistant to impact, puncture, penetration, fires or shocks. For example, the Nuclear Regulatory Commission has instituted certain tests in order to qualify a shipping container as satisfactory for shipping low/medium level radioactive (e.g., transuranic) waste materials. These tests are rather severe and in general they comprise:
1. A thirty foot drop test onto an essentially unyielding surface;
2. A forty inch drop test onto a six inch diameter steel bar;
3. A fire test at 1475.degree. F. for thirty minutes; and
4. A water immersion test.
Prior art shipping containers to date have generally been designed to provide shielding against the emissions of high level radioactive materials, such as nuclear fuel, and to withstand the severe stresses imposed by the physical tests mentioned above. Even so, the prior art has not provided a container which is light weight, and therefore economical to ship, and which provides the high level of containment and leak-tightness as required by the NRC regulations for transporting transuranic waste.
Therefore, there has been a need for a shipping container which can meet the stringent NRC requirements for shipping low and medium level nuclear waste materials, or other toxic waste materials, and which is light weight, easy to construct and economical to ship.